CVE-2020-21677
Summary
| CVE | CVE-2020-21677 |
|---|---|
| State | PUBLISHED |
| Assigner | mitre |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2021-08-10 21:15:07 UTC |
| Updated | 2026-04-24 12:56:58 UTC |
| Description | A heap-based buffer overflow in the sixel_encoder_output_without_macro function in encoder.c of Libsixel 1.8.4 allows attackers to cause a denial of service (DOS) via converting a crafted PNG file into Sixel format. |
Risk And Classification
Primary CVSS: v3.1 6.5 MEDIUM from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
EPSS: 0.002780000 probability, percentile 0.512160000 (date 2026-04-26)
Problem Types: CWE-787 | n/a
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 6.5 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H |
| 2.0 | [email protected] | Primary | 4.3 | AV:N/AC:M/Au:N/C:N/I:N/A:P |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
RequiredScope
UnchangedConfidentiality
NoneIntegrity
NoneAvailability
HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CVSS v2.0 Breakdown
Access Vector
NetworkAccess Complexity
MediumAuthentication
NoneConfidentiality
NoneIntegrity
NoneAvailability
PartialAV:N/AC:M/Au:N/C:N/I:N/A:P
NVD Known Affected Configurations (CPE 2.3)
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| heap-buffer-overflow in sixel_encoder_output_without_macro at encoder.c:814 · Issue #123 · saitoha/libsixel · GitHub | af854a3a-2127-422b-91ae-364da2661108 | github.com | Exploit, Issue Tracking, Patch, Third Party Advisory |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
Legacy QID Mappings
- 180609 Debian Security Update for libsixel (CVE-2020-21677)